Installation with MCSR Launcher
Launcher setup
After installing MCSR Launcher from the link above, open it and add your Microsoft account by going to Accounts ➔ Add Account.
Add Instance
In the launcher, go to New Instance, select MCSR Ranked, and press Create Instance. Finally, launch your new instance.
TIP
"MCSR" stands for "Minecraft Speedrunning", not for "Minecraft Speedrunning Ranked".